JPH08195228A - Power circuit - Google Patents

Abstract

PURPOSE: To enhance the reliability of detecting the amount of electricity remaining in batteries by eliminating the need to prepare plural kinds of battery packs according to service periods. CONSTITUTION: A structure in which two or more battery packs 1, 2 of the same form are mounted in parallel is formed, and a power circuit is provided with a CPU 7 to determine whether there are one or two battery-containing battery packs. The CPU 7 varies the way of issuing an alarm indicating the amount of electricity remaining in the batteries, depending on the number of battery-containing battery packs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit having a battery, and more particularly to a power supply circuit used in a portable input / output device.

[0002]

2. Description of the Related Art Conventionally, a portable input / output device can be carried by being driven by a battery, but only one battery can be mounted in the device. In the space that houses the battery,
It is necessary to select and install a small battery for short-time driving, and a large battery for long-time driving with the same output voltage. Also, when the device is used for either short time or long time depending on the work, it is necessary to prepare two types of batteries and a battery pack in which the batteries are inserted and a charger for each.

[0003]

Generally, when trying to extend the operating time by a battery, prepare a battery and a battery pack having the same output voltage but different shapes and battery capacities, and use a charger corresponding to the battery. Needs to be charged.
This means using a small battery for a short time and a large battery for a long time. There is a problem in that two types of battery packs must be prepared and a charger must be prepared for each.

If it is not possible to know in advance whether it is a short time or a long time depending on the work, it is unclear which battery and battery pack should be prepared, or by preparing only the battery and battery pack for a long time, There is a drawback that a large and heavy battery pack is used as necessary.

[Object of the Invention] An object of the present invention is that it is not necessary to separately use a small battery and a large battery, and the same battery and battery pack can be connected in parallel according to the application. By accurately detecting the remaining amount of
An object of the present invention is to provide a power supply circuit that can use the same battery regardless of work and has improved reliability.

[0006]

The power supply circuit of the present invention comprises:
(1) Two or more battery packs having the same shape can be connected, and (2) it has a means for detecting the output voltage of each battery pack and a means for detecting whether one or more battery packs are mounted with batteries. And (3) two or more battery packs are connected in parallel, and (4) a means for changing how to issue a battery level alarm is provided according to the number of battery packs in which the batteries are mounted. And

Further, another power supply circuit of the present invention is provided with means for detecting the temperature of the battery as well as the number of the battery packs in which the batteries are mounted, and the method of issuing the battery remaining amount alarm is changed depending on the number and the temperature. It is equipped with a means to make it.

[Operation] According to the present invention, it is detected based on the number detected by the means for detecting the number of battery packs in which the batteries are mounted, or by the means for detecting the number and the temperature of the battery in the battery pack. Check the battery remaining voltage based on the number of batteries and the temperature information that has been changed, and by changing the reference voltage value and checking it while comparing the remaining battery voltage with the reference voltage, the battery remaining alarm output signal at the optimum timing. Is output, it is possible to accurately detect the operable time (for example, remaining 3 minutes) regardless of the number of mounted batteries. Further, since the same battery pack is used, the productivity is good, the size of the battery is the same, and the standard is almost the same, so it is not necessary to prepare a plurality of chargers of different types.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a power supply circuit according to an embodiment of the present invention. In the figure, two battery packs 1 and 2 are connected to a power supply circuit 4. The power supply circuit of claim 1 corresponds to the entire circuit of FIG. The battery packs 1 and 2 each accommodate one battery having the same shape and the same output voltage. Battery packs 1 and 2 are positive (plus) and negative (minus)
In addition to the terminals, the terminals S for confirming the mounting of the battery are provided, and the positive and negative terminals and the terminals S are connected to the power supply circuit 4. For example, the terminal S is connected to the positive electrode, and the terminal voltage of the battery is output from the terminal S when the battery is mounted, but when the battery is not connected, no voltage appears at the terminal S. Therefore, it can be determined from the terminal S whether the battery is mounted in the battery pack.

The battery packs 1 and 2 are connected in parallel with each other via a backflow prevention diode 3. The backflow prevention diode 3 is connected to the positive electrode of each battery pack. As a result, when batteries are installed in both battery packs 1 and 2,
Due to the difference in the remaining battery level, the current from the higher output voltage battery is prevented from flowing into the lower output voltage battery.

The power supply circuit 4 has a DC-DC converter 6 and an analog / digital (A / D) converter 5 connected to the parallel output lines of the battery packs 1 and 2, and a CPU 7 having a microcomputer. DC-DC
The converter 6 is a DC-DC conversion circuit that converts the output voltage of the battery packs 1 and 2 into a predetermined DC voltage. A / D
The converter 5 converts the output voltage of the battery packs 1 and 2 into voltage data of digital value. The CPU 7 checks the number of the battery packs in which the batteries are mounted based on the outputs of the terminals S of the battery packs 1 and 2, and the remaining battery voltage based on the voltage data from the A / D converter 5. To detect. Further, the CPU 7 changes the level for checking the remaining battery voltage according to the number of battery packs in which the batteries are mounted, and outputs the battery remaining alarm output signal at the same remaining operable time regardless of the number of battery packs. Realize the functions that can be generated.

More specifically, the battery pack 1
The voltage detected by the A / D converter 5 before the battery is used is the same in the case where the battery is mounted in either of the cases 2 and 2, but the time when the battery can be used is naturally different. . That is, when the batteries are mounted on both the battery packs 1 and 2, the usage time becomes longer. Therefore, the CPU 7 has a terminal S for notifying the user of the battery output voltage (voltage data) and the number of batteries in order to accurately know the usable time of the batteries regardless of the number of battery packs in which the batteries are mounted. Based on the output, how to output the battery level alarm output signal is controlled. The A / D converter 5 and the CPU 7 are powered by the DC-DC converter.

FIG. 2 is a functional block diagram of the CPU 7, and FIG. 3 is a flow chart showing the operation of the CPU 7. In FIG. 2, the CPU 7 detects the number of battery packs in which batteries are mounted based on the outputs of the terminals S of the battery packs 1 and 2, and based on the number data from the number detection means 71. A battery remaining amount output generating means 72 for outputting an optimum battery remaining amount alarm output signal by changing the level for checking the battery remaining amount voltage, comparing with the voltage data from the A / D converter 5, and storing various data. RAM
73, and a storage unit 74 that stores a plurality of reference voltage data that serves as a reference for checking the remaining voltage.

As shown in FIG. 3, first, the CPU 7 detects the number of battery packs in which the batteries are mounted by the number detecting means 71 (step 101). Batteries are battery packs 1 and 2
In the case of being mounted, the voltage appears at each terminal S, and when not mounted, the voltage does not appear.
The number is detected by the presence or absence of the voltage from the terminal S. The RAM 7 stores the number data and the voltage data representing the output voltage of the battery.
3 is temporarily stored in step 3 (step 102). The remaining battery power output generating means 72 detects from the stored number data whether the number of the battery packs having the batteries mounted is one or two (step 1
03) In the case of one, the voltage data is compared with the first reference voltage data (step 104). For example, when the output voltage of the battery before use is 7.5V, the first reference voltage data is 5.0V. It is assumed that 5.0V is a voltage at which the remaining usage time of the battery is about 3 minutes. The comparison operation is repeated until the voltage data becomes 5.0V, and when the battery is exhausted to 5.0V, the battery residual amount output generating means 72
Generates a battery level alarm output signal (step 10
5, 106).

When the remaining battery power output generating means 72 determines that the number of battery packs with batteries mounted is 2, the voltage data representing the output voltage of the battery is compared with the second reference voltage (step 107). The second reference voltage data is a voltage lower than the first reference voltage data, and is 4.9 V, for example. The comparison operation is repeated until the voltage data becomes 4.9V,
When the voltage reaches 4.9V, a battery level alarm output signal is generated (steps 108 and 109). The first and second reference voltage data are both voltage data at the level that the battery will run out in about 3 minutes, and the life is naturally longer when two batteries are connected in parallel. The voltage data is lower.

As described above, in this embodiment, the CPU 7 detects the number of battery packs already mounted by the CPU 7 based on the output of the terminals S of the battery packs 1 and 2, and the number detection means 71. Check the voltage data of the remaining battery level based on the number data. By changing the reference voltage value and checking it while comparing it with the voltage data from the A / D converter 5, the remaining battery level alarm output signal is output at the optimum timing. Since the battery residual quantity output generating means 72 for outputting is included, the operable time (about 3 minutes in the embodiment) can be accurately detected regardless of the number of battery packs already mounted with batteries. In addition, since the same battery pack is used, the productivity is good, the size of the battery is the same, and the standard is almost the same, so there is no need to prepare a plurality of chargers. Also CPU
Since 7 is composed of a digital circuit, the power consumption is extremely small.

FIG. 4 is a circuit diagram showing a second embodiment of the present invention. In this embodiment, the temperature detecting elements 10 and 20 and the switches 11 and 12 are fixed in the battery packs 1 and 2, respectively. The temperature detecting elements 10 and 20 are elements whose voltage changes according to temperature, and are fixed in the immediate vicinity of the battery. The switches 11 and 12 are switches that close when a battery is housed, and are connected between the S terminal and the temperature detection element 10. The CPU 7 has means for detecting the temperature from the temperature detecting element 8 as well as the number of battery packs in which batteries are mounted from the S terminal. Since the switches 11 and 12 are closed when the batteries are housed in the battery packs 1 and 2, a closed loop is detected, the housing of the batteries is determined by this, and the temperature is detected by the voltage from the temperature detecting element.

Generally, in a battery, when the temperature is low, the chemical reaction inside the battery is lowered, and conversely, when the temperature is high, the chemical reaction becomes active. Therefore, even if the same terminal voltage is taken out, a sufficient current can be taken out when the battery temperature is high compared to when the battery temperature is low. In this embodiment, when the temperature is low, the CPU 7 increases the value of the reference voltage data to be compared with the voltage data from the A / D converter 5, and when the temperature is high, the value of the reference voltage data is decreased. This is because if the temperature is high, the current can be taken out even with a low battery terminal voltage. In this way, the operable time of the battery is predicted based on the number of battery packs already mounted and the temperature so that the battery life will be uniform regardless of the temperature.

Specifically, when a 7.5V battery is mounted on only one side of the battery pack, the first reference voltage data is set to 4.9V when the temperature is 20 ° C or higher, and 10 ° C to 20 ° C. Then, the first reference voltage data is 5.0V,
If it is less than 10 degrees, it will be 5.1V. When 7.5V batteries are mounted in both battery packs 1 and 2, the first reference voltage data is 4.8V when the temperature is 20 degrees or higher and the first reference voltage data is 10 degrees or higher and 20 degrees or lower. The reference voltage data is set to 4.9 V and 5.0 V when the temperature is 10 degrees or less.

In the embodiment described above, two battery packs are used, but even if two or more battery packs are used,
The same effect can be obtained by connecting the battery packs in parallel and setting the reference voltage data according to the number data. Further, the number of batteries accommodated in one battery pack may be two or more.

The shape of the battery pack is not particularly limited. Further, the terminal S is provided in the battery pack as a means for detecting the number of battery packs in which the batteries are mounted, but the number may be notified to the CPU 7 by another input means.

Further, the battery residual quantity output generating means 72 (FIG. 2)
The battery remaining amount alarm output signal generated by the above may be a signal of a specific code or a signal for displaying a specific display.
In addition, the number of battery packs in which batteries are mounted and characters indicating an alarm may be displayed. When displaying a character, it is necessary to store the character data in the CPU in advance.

FIG. 5 is a circuit diagram of a portable input / output device having the power supply circuit of FIG. 1 or 4. In the figure, CPU
9 operates according to a program stored in the ROM 10, and data input from the external interface 12 or the keyboard 13 is stored in the RAM 1 and displayed on the display unit 8. When the input work from the keyboard is completed, the RAM 1 is sent from the external interface 12 to the outside.
The data in 1 is output. Each circuit is powered by the power output from the power circuit 4 (the output of the DC-DC converter 6 in FIG. 1). Further, when the power supply circuit 4 outputs a battery level alarm output signal generated based on the voltage of the batteries mounted in the battery packs 1 and 2 and the number of battery packs mounted with the batteries, the CPU 9 receives the signal. Then, the battery level alarm is displayed on the display unit 8. When the battery level alarm signal is character data, the characters of the character data are displayed on the display unit 8.

[0025]

As described above, according to the present invention, (1) a structure in which two battery packs having the same shape can be mounted in the device, (2) a means for detecting the output voltage of the battery pack, and a battery A means for determining the number of mounted battery packs is provided, (3) two battery packs are connected in parallel, and (4) how to issue a battery level alarm depending on the number of battery packs mounted with batteries. By providing a means for changing, 1
By preparing multiple types of battery packs, the operator can mount the batteries in only one battery pack when using for a short time, and can operate in a lightweight state. There is an effect that selection can be made only by the number of one type of battery pack, such as mounting a battery in the battery pack. Further, there is an effect that the operable time can be accurately detected and notified to the operator regardless of the number of battery packs.

[Brief description of drawings]

FIG. 1 is a block diagram of a power supply circuit according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a CPU of the power supply circuit shown in FIG.

FIG. 3 is a flowchart showing an operation of the CPU of FIG.

FIG. 4 is a block diagram of a power supply circuit according to a second embodiment of the present invention.

5 is a block diagram of a portable input / output device having the power supply circuit shown in FIG. 1 or 2. FIG.

[Explanation of symbols]

 1 Battery pack 2 Battery pack 3 Backflow prevention diode 7 CPU

Claims (7)

[Claims] 1. A plurality of battery packs in which batteries having the same output voltage and substantially the same standard are mounted and connected in parallel to each other,
Voltage detection means for detecting the output voltage of the battery pack,
A number detecting means for detecting the number of battery packs in which the batteries are mounted, and an alarm indicating that the battery residual voltage detected by the voltage detecting means has decreased in accordance with the number detected by the number detecting means. A power supply circuit including a battery residual quantity output generating means for controlling generation of an output signal. 2. The battery remaining power output generating means changes the reference voltage value for checking the remaining battery voltage based on the number detected by the number detecting means, the battery remaining voltage and the The power supply circuit according to claim 1, further comprising means for comparing with a reference voltage value and generating the alarm output signal according to the result. 3. The battery remaining amount output means stores the reference voltage value according to the number of battery packs in which the batteries are mounted, and the battery remaining capacity output means based on the number detected by the number detection means. Means for selecting the reference voltage value for checking the remaining voltage from the storage means, and means for comparing the battery remaining voltage with the reference voltage value and generating the alarm output signal according to the result. A power supply circuit as claimed in claim 1 including. 4. The power supply circuit according to claim 2, wherein the reference voltage value becomes a small value every time the number detected by the number detecting means increases. 5. The battery pack has a terminal for generating a signal indicating whether or not a battery is mounted, and the number detecting means detects the number based on a signal from the terminal. Power supply circuit described in. 6. The power supply circuit according to claim 1, further comprising a diode that blocks a current from flowing between the battery packs due to a difference in remaining battery voltage of the battery packs. 7. A plurality of battery packs in which batteries having the same output voltage and substantially the same standard are mounted and connected in parallel to each other,
Voltage detection means for detecting the output voltage of the battery pack,
A number detecting means for detecting the number of battery packs in which the batteries are mounted, a means for detecting the temperature of the batteries in the battery pack, a number detected by the number detecting means and a temperature detecting means. A power supply circuit including: a battery residual quantity output generating means for controlling generation of an alarm output signal indicating that the battery residual quantity voltage detected by the voltage detecting means has decreased according to temperature.